C127 w/ CP370 or 470

[MAK1377]

I recently sold all of my Raymarine electronics (MFD, AP, DSM, & Radar) and upgraded to a C127 (and other Raymarine replacement products). I fish the Great Lakes. I currently utilize a 600W P66 Transducer, but am considering a CP370 or CP470 with upgraded transducer. I typically do not fish deeper than 200-250 feet and spend most of my time in water less than 150 feet but I do often target fish on the bottom of the lake (Lake Trout) with downriggers. I am very interested in having the ability to see as much detail as I can for fish, baitfish, thermoclines, and bottom as is practical. Acknowledging that I will need to upgrade my transducer, which unit, CP370 or CP470 might be more practical for the type and depth of fishing that I do? Do I need a CP470 if I only fish less then 250 feet to see the same level of detail as I would with a CP370? Is the CP470 really only targeted towards fishing significantly deeper water?